Eucalyptus Insects, Diseases, and Adverse Aboitic Factors

137 Pages·2017·5.98 MB·English

by  Scott's Laptop

Advanced Forest Protection, Inc. 11/14/2011

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Guide to Potential Insects, Diseases, and Other Damaging Agents of
Eucalyptus in the Southeastern United States

Prepared by:
Advanced Forest Protection, Inc.

Other Contributors:

Editor:
Dr. Ronald F. Billings, Texas Forest Service

Guide for public use and educational purposes only.
Not for sale.

Cover photos: Upper right: Eucalyptus longhorned borers, photo by J. K. Clark, University
of California Statewide IPM Program. Left: Eucalyptus stand in south Florida, photo by Ed
Barnard (Florida DACS, retired); Bugwood.org.

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Table of Contents
Preface....................................................................................................................................... 1
Introduction ............................................................................................................................... 3
Literature Review and Selection of Damaging Agents................................................. 4
Organization and Content ............................................................................................. 5
Definition of Terms....................................................................................................... 5
Signs and symptoms ..................................................................................................... 6
Classification of fungi ................................................................................................... 7
Insect Pests .............................................................................................................................. 10
Sap-sucking insects ..................................................................................................... 10
Blue gum psyllid (Ctenarytaina eucalypti ).................................................... 10
Red gum lerp psyllid (Glycaspis brimblecombei) .......................................... 11
Other psyllids .................................................................................................. 11
Winter bronzing bug (Thaumastocoris peregrinus ) ...................................... 12
Gall-forming insects.................................................................................................... 13
Blue gum chalcid (Leptocybe invasa) ............................................................. 13
Other gall wasps .............................................................................................. 15
Leaf and shoot feeding insects - defoliators ............................................................... 16
Eucalyptus tortoise beetles .............................................................................. 16
Australian gum tree weevil (Gonipterus scutellatus) ..................................... 17
Purple moth (Sarsina violascens) ................................................................... 18
Texas leaf-cutting ant (Atta texana) ................................................................ 20
Phloem and wood-boring insects ................................................................................ 23
Eucalypt longhorned borers (Phoracantha semipunctata and P. recurva) ..... 23
Diseases................................................................................................................................... 23
Propagation diseases ................................................................................................... 23
Cylindrocladium disease ................................................................................. 23
Botrytis cinerea ............................................................................................... 23
Pithium spp. .................................................................................................... 23
Rhizoctonia solani ........................................................................................... 23
Foliage and shoot diseases .......................................................................................... 24
Cylindrocladium leaf spot and blight .............................................................. 24
Mycosphaerella leaf diseases .......................................................................... 24
Phaeophleospora leaf disease ......................................................................... 24
Other leaf diseases: Alternaria, Aulographina, Cryptosporiopsis,
Fairmaniella, Harknessia, Microsphaeropsis ................................................ 24
Eucalyptus rust (Puccinia psidii) .................................................................... 24
Canker and dieback diseases ....................................................................................... 24
Botryosphaeria dothidea-ribis complex ......................................................... 25
Ceratocystis wilt (Ceratocystis fimbriata) ...................................................... 25
Coniothyrium canker ....................................................................................... 25
Eucalyptus canker (Chrysoporthe cubensis) ................................................... 25
Pink disease (Erythricium salmonicolor)........................................................ 25
Bacterial wilt ................................................................................................... 25
Stem and root rots ....................................................................................................... 26
Armillaria, Ganoderma, Phellinus stem and root rot ..................................... 26
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Phytophthora root rot ...................................................................................... 26
Decline - Diseases of complex origin ......................................................................... 26
Non-infectious Disorders (Abiotic Agents) ............................................................................ 26
Rooting problems ........................................................................................................ 27
Weather ....................................................................................................................... 27
Excess soil moisture .................................................................................................... 27
Fire .............................................................................................................................. 27
Chemical injury ........................................................................................................... 27
Nutrient deficiencies ................................................................................................... 28
Survey and Diagnosis of Tree Health Problems ..................................................................... 43
Survey, Monitoring, Detection, and Evaluation ......................................................... 43
Diagnosis of Plant Health Problems ........................................................................... 44
Preparation, equipment and supplies .............................................................. 44
Fieldwork – How to review the site and examine the plants for clues ........... 45
Diagnostic Questionnaire (Data Form) ........................................................... 46
Where to find help and send samples ............................................................. 46
Collecting, handling, and shipping samples for laboratory diagnosis ............ 47
Guidelines for taking digital images ............................................................... 48
Chemical analysis of nutrient concentrations in plant tissues ........................ 51
Eucalyptus Insect and Disease Management Strategies ......................................................... 53
Avoidance of New Pest Introductions ........................................................................ 53
Risk Management ....................................................................................................... 53
Insect- and Disease-Resistant Planting Stock ............................................................. 54
Managing Tree Health and Avoiding Stress ............................................................... 55
Matching species, provenance, and variety to the planting site ...................... 55
Silvicultural treatments ................................................................................... 56
Biological Control ....................................................................................................... 56
Pesticide Use ............................................................................................................... 57
Glossary of Terms ................................................................................................................... 58
References ............................................................................................................................... 67
Additional Resources .............................................................................................................. 82
Eucalyptus Experts by Specialty ................................................................................. 82
Forest pathology.............................................................................................. 82
Forest entomology .......................................................................................... 82
Forest nutrition and silviculture ...................................................................... 83
Web sites ..................................................................................................................... 83
Eucalyptus – General information and management guidelines..................... 83
State and federal agency forest health services ............................................... 84
Resources on insects, diseases, and forest nutrition ....................................... 85
Survey and diagnostics ................................................................................... 86
Weather forecast, current conditions, historical data ...................................... 86
Pesticide labels and material safety data sheets .............................................. 87
Appendix A - Plant Health Data Sheet ................................................................................... 88
Appendix B – List of Fungi Synonymies and Hosts .............................................................. 90

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Preface

The genus Eucalyptus is diverse with more than 700 species, often collectively referred to as
“eucalypts,” although some are now classified under the genus Corymbia or Angophora. These
woody plants belong to the myrtle family, Myrtaceae, and have adapted to a broad range of sites
and climatic conditions across their native range in Australia and New Guinea. Many Eucalyptus
species grow exceptionally fast and have fiber qualities suitable for manufacturing high-quality
white paper. The wood is also used for building materials, high-quality charcoal, and fuel wood in
many parts of the world, and may be utilized in the future for carbon sequestration and biofuel
production. Eucalypts can be planted at high densities in plantations, grown in coppiced
production, and harvested at rotations of 10 years or less. Many eucalypts will grow on poor soils
with no supplemental irrigation.

Extensive commercial plantations of Eucalyptus have been established in South America (Brazil,
Chile, and Argentina), sub-Saharan Africa (Republic of South Africa, Zambia, and Malawi), and
the Mediterranean basin (Spain, Portugal, Italy, Tunisia, Algeria, and Israel). In addition to being
used extensively for commercial timber and fiber production, eucalypts have also been planted in
many parts of the temperate and subtropical world as windbreak and ornamental trees (Doughty
2000, as cited in Paine et al. 2010).

Eucalypts have been grown in the United States for well over 100 years, but commercial
plantations have been limited in size and restricted mostly to the southern parts of California and
Florida. Eucalypts were initially introduced into California as a timber species, but growth and
wood characteristics were unsuitable. Nevertheless, over 90 species of eucalypts have been
widely planted as landscape and windbreak trees across much of southern California (Doughty
2000, as cited in Paine et al. 2010). Lykes Bros, Inc. has grown eucalypts in plantations for over
30 years in south Florida and currently manages about 11,000 acres of E. grandis for the
production of landscape mulch (http://lykesranch.com/). Eucalypts were first introduced in
Hawaii in the late 1800s, but only recently considered for short-rotation commercial production
(Whitesell et al. 1992).

The forests in the southeastern United States have been referred to as the “wood basket” of the
nation because of the extensive suitable land base and the large amount of timber produced. Yet
sources of hardwood pulpwood have become relatively limited in the region and growth rates are
far inferior to those being produced in eucalyptus plantations in many other parts of the world. The
commercial success of eucalyptus plantations in other parts of the world has led to a number of
planting trials in the southeastern U.S. during the past 30 years (Jahromi 1982; NCSU 2008).
However, these early trails were limited in the number species and provenances tested and largely
failed due to periodic freeze damage and relatively poor growth rates.

“However, contemporary breeding practices, expanded species and provenance testing, and
genetically-modified varieties could reduce the susceptibility of planting stock to frost damage and
yield trees adapted to growing in expanded areas” (Paine et al. 2011). A number of initiatives are
currently underway to significantly increase the distribution and acreage of eucalyptus plantations
in the southeastern U.S. These programs are primarily focused on increasing frost tolerance and
growth rates through expanded species selection trials, varietal selections, traditional breeding, and
molecular modifications.
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As Eucalyptus plantations have expanded worldwide, exotic and native insects and diseases are
threatening growth and productivity. The establishment of plantations from clones, selected
primarily for good growth and product quality, requires particular vigilance with regard to the
susceptibility of individual clones to pests and diseases. The "absolute rule" coined by Zobel and
Talbert (1984): "exotic plantations will be attacked by one pest or another," will certainly apply to
eucalyptus plantations in the southeastern U.S. The probability of incurring significant losses to
insects and diseases will become progressively greater with an increase in acres and ages of
densely planted, genetically homogeneous eucalyptus plantations (Turnbull 2000).

It is critical during the early stages in the development of an expanded eucalyptus resource in the
southeastern U.S for everyone involved in the process to be vigilant, recognize tree health
problems as soon as they occur, and take appropriate action to avoid potential devastating losses.
Equally important is to foster the participation of experts to assist with diagnosis and evaluation of
eucalyptus health problems and to encourage research studies that lead to a better understanding of
eucalyptus host susceptibility and the development of practical management alternatives.

Forest industry in the southeastern U.S. recognizes the potential importance of insects, diseases,
and other non-infectious disorders in eucalyptus culture and has advocated a proactive approach to
maintaining healthy forest plantations. In an initial action, MeadWestvaco, International Paper,
and the Forest Productivity Cooperative conceived and supported the preparation of this document
designed to foster healthy plantations and integrated pest management, including prevention, early
detection, and prompt suppression action. Advanced Forest Protection, Inc. was engaged to
prepare a framework and the initial content for a Guide to Potential Insects, Diseases, and Other
Damaging Agents of Eucalyptus in the Southeastern U.S. (i.e., “Guide”).

Preparation of this Guide was particularly challenging because of a lack of experience and
published information on insects and diseases of eucalyptus in the southeastern U.S. Also, the
dynamic, evolving taxonomy of fungi associated with eucalypts has complicated this task
considerably. Thus, the focus of this guide has been on developing overviews of selected insects,
pathogens, and non-infectious diseases that are representative of the various types of damage
and/or have caused significant problems on eucalypts in various parts of the world, especially in
California and South America. Strong emphasis has been placed on survey, sampling, diagnosis,
and how to obtain additional information and assistance.

This Guide is not a definitive “final document,” but rather a framework upon which individual
insect and disease summaries and other information can be added as needed through field
experience, research studies, and ever-changing information available on the internet.

We would like to acknowledge Dr. Ed Barnard (retired), Florida Department of Agriculture and
Consumer Services, for providing technical guidance and literature resources, Dr. Timothy Paine,
University of California, Riverside, for providing technical information, the University of
California, Agriculture and Natural Resources for providing photos of eucalypt pests and damage,
Celso Foelkel, Celsius Degree, for providing contacts and literature sources, Ted Garman, Lykes
Bros. Inc., Ranch Division for providing literature and hosting a field trial visit, Anthony Elledge
for assistance with digital image sizing and management, and Dr. Ronald F. Billings for his expert
review of an early draft of this Guide.
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Introduction

“Losses through reduced growth or mortality attributable to pests, diseases, and abiotic
disturbances are generally less in intensively managed, planted forests than in natural forests.
Among plantation forests, the most healthy forests are those of exotic species growing a long way
from their native range (e.g., Pinus radiata D. Don in New Zealand) and the least healthy ones are
those of indigenous species (e.g., Eucalyptus nitens (Deane & Maiden) Maiden in Tasmania). The
better health of plantations is a reflection of the generally good growing conditions, the proper
matching of site to species that is possible in artificial culture and in the case of exotic species, the
freedom from the many pests and diseases present in the native habitat of exotics” (Godgil and
Bain 1999). Eucalyptus species planted outside their native range have been largely pest free
through most of their 150 plus years of existence. This is due mainly to the fact that in the mid-
19th century when eucalypts were widely distributed around the world, seed propagation was the
rule and thus, foliage- sap-, and wood-feeding insects were not moved with the seeds (Doughty
2000).

However, during the last several decades, many significant insect and disease problems have been
documented on eucalypts in many parts of the world. This troubling trend is probably associated
with the massive increase in the movement of people and international commerce, including
eucalyptus plant materials and wood products, in the current global economy (Paine et al. 2010,
2011).

Eucalyptus planted in the United States has been restricted primarily to southern and central
California, a few plantations in central and south Florida, and widely scattered ornamental
plantings across the southern U. S. Although eucalypts have been relatively free of insect pests
and diseases through most of the time since being introduced into the U. S., a marked number of
exotic pests have been found on eucalyptus in recent years, especially in California.

Many of the important insect pests and diseases that have invaded eucalyptus-growing regions
around the globe are species introduced from the native range of eucalypts. This is the case for the
extensive eucalyptus plantations in South America. However, in Brazil, several of the more
serious pathogens and a few of the insect pests, primarily defoliators, have shifted from native
hosts onto eucalypts. Generally, these cross-over insects and pathogens are species with a broad
range of hosts, or are species associated with related plants in the Myrtaceae family. Groups of
insects and diseases that have followed eucalypts from Australia to many locations around the
world include: psyllids, gall wasps, leaf-feeding beetles, and a large group of foliage diseases.
Examples of insects and diseases that have shifted to eucalypts in South America include: pink
disease, eucalyptus canker, canker stain, guava (eucalyptus) rust, and several caterpillar species.

The Myrtaceae are widely distributed in the tropics and subtropics of the southern hemisphere.
This family includes commonly known plants such as guava, allspice, cloves, as well as eucalypts.
However, the Myrtaceae are absent from North America, except in cultivation, which may
represent a lower risk of pests switching from native host plants to eucalyptus in the southeastern
U.S.

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Literature Review and Selection of Damaging Agents

A comprehensive account of eucalypt diseases worldwide was recently provided by Keane et al.
(2000). Paine et al. (2010) gave an overview of the insect pests of eucalyptus around the world,
but a thorough, in-depth compilation of work on insect pests associated with eucalyptus
worldwide is not available. Outside of Australia, much of the work published on eucalypt insects
and diseases has been conducted in New Zealand, Brazil, and South Africa. In the U.S.,
entomologists in California have conducted considerable work on biology and control eucalyptus
insect pests during the past two decades (Hanks et al. 2000; Paine et al. 2000; Dahlsten et al. 2003;
Paine and Millar 2003; Paine and Dreistad 2007; Millar et al. 2009; Paine et al. 2009), but only an
index is available for the diseases of eucalypts in California (Tidwell 1990). In the southeastern
U.S. little has been published beyond a chapter on eucalyptus diseases in a hardwood handbook
(Kuhlman and Barnard 1979) and a couple extension bulletins for insect pests in Florida (Halbert
et al. 2008; Wiley and Skelley. 2010).

Relatively few eucalyptus trees have been planted in the southeastern U.S., primarily due to
insufficient cold tolerance in the planting stock tested to date. Thus, there are few experts with
eucalyptus experience in the region and few insects and diseases have been documented in any
detail. One can only speculate as to which insects and diseases may become important in the
future as larger commercial plantations are developed.

Thus, this guide is not intended to be a definitive and comprehensive review of eucalyptus pests
and diseases in the region, but rather a resource for plantation managers and field personnel that
includes descriptions of representative potential insect pests and diseases followed by considerable
information on how to prevent, monitor, diagnose, and sample damage agents and where to find
additional information and professional assistance.

The approach taken was to review the insects and diseases which have been reported on eucalypts
in the U.S., as well as those that originated from Australia, or switched from native hosts, and
have caused significant damage in eucalyptus plantations around the world. A preliminary
comprehensive list of damaging agents was compiled based on a number of key references,
including: world and regional reviews (Kuhlman and Barnard 1972; Tidwell 1990; Keane et al.
2000; Santos et al. 2001; Feirrera and Milani 2002; FAO 2007a, 2007b, 2009; Paine et al. 2010,
2011); two pest risk assessments for importation of eucalyptus logs into the U.S. (Kliejunas et al.
2001, 2003), eucalyptus insect and/or disease field guides for other countries/regions (Baldini
2006; Old et al. 2003; Ramanagouda 2007), among others. This list was then consolidated into a
shorter, featured damage-agent list, primarily to include those already in the U.S., those that have
caused significant damage in multiple locations around the globe, and those that represent various
types of damage. Insects and diseases are listed separately, and within each they are grouped
according to damage types. Non-infectious diseases are listed separately (Table 1).

A comparison in Table 1 of the number of insects and diseases reported on eucalypts in California
and Florida reveals that there are considerably more insects in California and more diseases in
Florida. Several reasons for this difference could be considered, but one obvious possibility is that
southern California has a dry Mediterranean climate, perhaps more conducive to insect population
development, while Florida and the Gulf Coast have a more humid semi-tropical climate, which
would be more conducive to disease infection and growth. Thus, it may be assumed that the insect
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pests and diseases most likely to show up on eucalypts in the southeastern U.S. will differ
substantially from than those affecting eucalypts in California.

Organization and Content

Each featured insect, disease, and other damaging agent is described using standard headings: 1)
common and scientific names, 2) distribution, hosts, and impact, 3) detection (what to look for), 4)
biology, 5) monitoring, and 6) risks and management options. Accounts are based on summaries
provided in other field guides, pest alerts, and selected literature references. Color photographs of
damage symptoms, disease signs, and insect stages are presented for each featured pest and
disease. These images have been derived with permission from a variety of sources from around
the world.

This Guide is primarily aimed at helping field personnel with the diagnosis and evaluation of
health problems of eucalypts. Thus, identification of each featured causal agent is based on visible
signs and symptoms. Descriptions and illustrations of microscopic characteristics of pathogens
are generally not included, even though these structures may be essential for identification. Also,
personnel involved in eucalyptus culture in the U.S. will certainly encounter many damaging
agents not included in this guide, or their identity may be uncertain based on the information
presented.

For this reason, substantial sections following the individual pest descriptions are provided in the
guide to help with survey, sampling procedures, digital imagery, diagnostic labs, specialist
contacts, general management procedures, and where to obtain additional information. Also, links
to a number of websites are provided by topic to assist with finding further information on
eucalyptus pests, pesticide labels, weather conditions, etc. Contacts with specialists should be
cultivated early to assist with identifications of insects, pathogens, and nutrient disorders. These
connections would also be useful in the future should greater involvement and commitment be
needed to deal with serious problems requiring the development of appropriate management
alternatives.

Definition of Terms

Many technical terms are used to describe symptoms of insect and disease damage, insect stages,
and fungal structures. A “Glossary of Terms” is provided just prior to the References section in
this guide to assist non-specialists who may be unfamiliar with the terminology used here or in
other references to forest insects and diseases. A few terms that are central to the organization and
presentation in this guide are defined here for clarification.

Pest: The term pest has been used broadly to refer to all organisms (insects, other animals, weeds,
plant pathogenic fungi, viruses, etc.) that are detrimental to humans or human concerns. It
also has been used more narrowly to include only harmful animals (insects, rodents, etc.).
In this guide, the term pest is used to refer only to animals, primarily insects, and does
not include diseases caused by pathogenic fungi, viruses, and abiotic agents, which
conforms to the use of the term in several of the references, especially international work,
cited in this guide. Parasitic plants and weeds are not considered in this guide.

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Disease: An impairment of the normal state of a plant that interrupts or modifies its vital
functions. <http://www.britannica.com/EBchecked/topic/463327/plant-disease>

Pathogen: Organisms (usually very small or microscopic) such as bacteria, fungi, and viruses that
cause or induce disease in their host. A pathogen is the causal agent and the disease is the
manifestation of the damage to an organism caused by the pathogen.

Non-infectious disease: Non-infectious tree diseases are those caused by non-living agents. This
type of disease is not transmitted from one plant to another.
<http://www.na.fs.fed.us/spfo/pubs/howtos/ht_non/non_all.htm.> Non-infectious diseases
are also referred to as abiotic diseases and include weather-related disturbances (drought,
excessive moisture, hail, ice, and wind storms), fire, and nutritional disorders.

Signs and symptoms

Evidence of plant health problems comes in a variety of forms, often referred to as signs and
symptoms. A sign is the insect or disease-causing organism itself, or any part or product of the
pest that is visible on the plant. Life stages of pests, powdery mildew, or the fruiting bodies of a
fungus are signs. A symptom is a response by a plant to a pest or injury that can be seen in the
absence of the causal organism. Declining growth rate, abnormal growth, dieback, plant exudates,
and decomposition are symptoms of damage caused by insects, diseases and other disorders.

Insect life stages (eggs, larvae/nymphs, pupae, adults). Insects undergo major changes in form
and behavior as they develop and mature. Most plant-feeding insects lay eggs, which may be
hidden in plant tissues or attached on plant surfaces. Insects have two main types of life cycle,
“gradual” or “incomplete” and “complete” transformation (metamorphosis), as they grow
through several molts from the immature to adult stage. The immature stages of insects such as
grasshoppers that undergo gradual change are referred to as nymphs, which look much like the
adults, except they do not have wings or mature reproductive organs. They also feed in a similar
manner and habitat as adults and do not have a pupal stage. In contrast, insects that undergo a
complete change in form start out as eggs, then develop into caterpillars or grubs (larva; pl.
larvae) and have an inactive “resting stage,” pupa (pl. pupae), through which they change from a
larva into an adult (for example, caterpillar to butterfly, or grub to beetle). The larvae of insects
with complete metamorphosis have a dramatically different form and may feed in a different
manner and location from that of the adult stage.

Plant disease signs and symptoms. Plant diseases may be caused by fungi, bacteria, viruses,
abiotic agents, or combinations of these. The causal agents of diseases are usually too small to be
seen with the naked eye, or are absent in the case of abiotic agents. Diseases often are initially
diagnosed based on host damage symptoms, such as, mortality, dieback, cankers, tissue necrosis,
staining, or decomposition. Initial diagnosis often must be confirmed through laboratory culture
of the causal organism and identified based on its microscopic, DNA, or chemical characteristics.
The relatively few signs of fungal pathogens that are visible in the field include: conks,
mushrooms, rust spores, mycelial mats, and bacterial ooze.

Damage types. Insect pests are often grouped according to the type of feeding or part of the plant
they damage. In this guide, insect pests are organized according to the following categories: leaf
and shoot feeders (defoliators), sap sucking insects, gall forming insects, phloem and wood borers.
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